Construction of ships&#39; davits



Jan. 12 1926.

J. R. CLAY ET AL CONSTRUCTION OF SHIPS DAVITS 1,569,715 J. -R. CLAY ET AL CONSTRUCTION OF SHIPS DAVITS Jan 12 1926 2 Sheets-Sheet 2 Filed Feb. 16, 1924 i: s'rr means JAMES RICHARD CLAY, on BLUNDELLSANDS, AND JOHN sco'r'r VALENTINE nannison, or wArEnLoo, ENGLAND. r

CONSTRUCTION OF SHIPS DAVITS.

Application filed. February 16, 1924. Serial No; 693,369.

To all whom z'tm'ay concern: 7 q

Be it known that we JAMns RICHARD CLAY and JOHN Scorr VALENTINE l'lnnnison, subjects of the King of England, and residing e at Blundellsands and Waterloo, respectively,bth in the county of Lancaster, England, have invented Improvements in and Connected with the Construction of Ships Davits, of which the following is a specification. v

This invention has reference to ships .davits mounted. and working on horizontal pivots,

the lower part of the davit has a rack which 95 merged, lubricated, and protected.

The davit itself, that is the outerand longer part, and the lower or inner and short part within the case, are in some cases, all in one piece; whilst in other cases 1t may be made in separate parts, separately connected up with a journal or trunnion pin mountedin bearings'in' the casing. According to this invention the inner or lower end or part of the davit is provided with a quadrant having ordinary spur wheel type of teeth, with which a small toothed spur pinion meshes; and this pinion is coupled up with or formed in one with a large worm wheel, the transverse spindle of which is mounted in bearings in the casing; and meshing with this worm wheel is a worm, which is adapted to be operated through a spindle or the like from outside the casing. In some vcases, in addition to the worm gearing above described, anadditional gearing, such as a spur gearing, is employed in connection'with the worm'shaft, for driving same; namely, on this driving shaft there will be mounted a large spur wheel, say within the casing,-wh ile meshing with it is a pinion on a shaft carried in. the casing, and revolved orgoperated from-outside-by a crank handle or'power.

andtheir operating gear, wherein is operated upon by toothed gearing, and

The davit carries outside its supporting bearing, a semicircular or arcuate shield,

whichworks over a correspondingly formed 1 inner frame or case fixed 0n the casing,

parts of which near the centre form bearings to receive the trunnion or pivot pin of the davit; and this part is provided with Y an arcuate aperture or frame through which the davit can move in its throw. Thus theshield'carried by the davit'always covers and-protects this aperture or slot for all positions of it; and therefore access of spray or water to the casing from the outside is prevented.

The casing, at the inner end, is provided with a roof or hood portion, projecting up from the top of the casing body and forming a separate part attached to the body or main easing, into which portion the upper end of the quadrant will pass when the davit is lowered; and a door or cover is provided on ,the inner end of the casing, through which the worm shaft bearings and parts may be inserted, and it serves as a means ofaceess to the interior for inspecting the gear, and other purposes as may be required.

The annexed drawings, in conn tion with which the invention will 'be further described, show a davit gear having'the construction and arrangement of parts above specified. V

'I'n'these drawings, Figure 1 is a sectional elevation; Figure 2 is an outside end View; and Figure '3 is a cross section showing the gear. r

or box in which the lower part of the davit,- and the gear parts are disposed and work; 2, 2* are the covers of the box 1; 3 is the Referring to the drawings, 1 is the casing v I upper part of the davit arm or davit; and. V

4: is the quadrant which is within the casing 1 and in the case shown, is in one with or forms part of the davit arm 3.

6 is the trunnion pm of thedavit, which i in the case shown, is separate from thedavit and passes through same ora bush therein, its ends being supported and fixed in bearings 25 on the casing 1, as hereafter explained.

pinion 7 mounted on a spindle 8, supported f The quadrant la-has on itslower face a I iii) , small.

jects through the cover and fixed in bearings 9 on the casing 1, and held in place by plates 8*, secured to the ends of the bearings 9.

The boss or hub 10 of the spur pinion 7 projects out on one side, and on it is keyed or fixed a worm wheel 11, with which meshes a; worm 12, formed or fixed on the spindle l3, which is supported in bearings 14:, fixed on. the inside surface of the casing 1 by bolts or other means.

The spindle 13 projects tln'ough a cover on the inner end oi the casing 1. (which is practically open when the cover is removed), and by the rote'ltion of this shaft, say through a removable hand crank 2-3, the whole davit, gear operated,

In this gear the only oblique resultant of load or force on members of it, is that between theworm 12 and the worm wheel 11; and inasmuch as at this point or part of the train of gearing by its character, the pressure on it at any time is relatively small, the lateral or oblique strain on the teeth of the worm gearing, that is both when operating the gear by hand, when lowering a load on the davit or gear, or when lifting a load; whilst the part of the gear which is subject to the full weight and load, namely, the toothed quadrant 5 and pinion 7, has no obliqueor lateral thrust imparted felt; that is the pressure or'thrust is directly in the'planes oi the wheels themselves; and consequently no wringing or like objectionable strain or thrust comes upon the davit arm and quadrant.

In the case shown, the worm 12 and its shaft 13 are made in one, and may be assumed to be made of cast or wrought metal; the outer and inner ends being supported in bearings 14 fixed on the inside of the casing; and between one of these bearings 14:, and the shoulderllfi on the end of worm 12, there is a ball bearing 17, forming a ball bearing thrust block, against which the endwise pressure on the worm, exerted by the load on the davit (reduced in degree owing to the character of the gearing) is taken; and this as stated is relatively On the worm spindle 13, within theend with which meshes a small pinion 19, fixed on, a: short spindle in a bearing 21 on the cover 15, and a suitable bearing 22 on the inside oil. the casing 1'. This spindle 20 pro- 15 similarly as the spindle 13, and it is provided on its outside with a square or flatted end, similar to that of 13, and is adapted to receive a handle 23, which when moving the davits outboard will be on the spindle 13. When thedavit brought up and inboard, the crank 23 is taken from the spindle 13'; and placed on the spindle 20, and a chase is thus obtained:

further large pur- The oil or liquid level in the casing 1 is marked LL.

The trunnion pin 6,ias stated, is mounted in bearings 25, on the sides of the casing l, and is held in place by plates 26, which are fastened to the ends of the bearings by screws, bolts, or the like and one end of the trunnion is reduced, and projects through the plate 26, and has a sheave or pulley 27 on its end for the purpose of guiding the wire or manilla falls from the boat lowering appliance to the lowering tackles attached to the head of the: davit.

The portion of the separate casing cover into which the inner end of the quadrant passes when the davit is down, as indicated. by the dotted lines, is marked 2", and rojects up and is fastened. onto the top 0 the casing 1. i

The davit 3 has fixed on it an arcuate lid 29, and-the sides of the casing project up above the bearings on each side,-and are semi-circular in form. This neck portion of the casing through which the davit arm 3 passes, has fixed across it a neck piece in the form, of an open frame casting" 30, through which the lower portion of the davit arm 3 works, and directly or closely over which the lid 29 fits and works; and the lid having a dependingflange which lies over the neck frame 30, a complete cover to the neck of the box 1 isprovided in all positions of the davit arm and its lid 29'.

The lid 29 may be in halves, as in the case shown, and provided with flanges, so that the two halves may be placed together over the arm, and clamped together and on it, and fixed thereby any suitable means.

The neck frame 30 has a depending flange at each side which comes down on the outside of the circular upwardly projecting side parts of the casing lgwhich forms the neck of the casing; and the frame has a lip 31;, to which the upper edge ofthe' cover part 2* is attached, and the side edges of the cover are secured by screws on the like to the edges: of the neck and the horizontal part of the casin and its lowenend is 'turned up as shown in Figure 1 and attached to the cover part 2, which projects up as shown, and isbolted or similarly fastened by flanges on the top of the casing.

The backward position of the davit is con trolled by bar 33 across the neck 01 the casing.

Bythe trunnion pin 6 being loose, and inserted in position end wise in' the bearing 25 of the casing 1', and a bearing sleeve 6 being provided in the boss of the davit, the neck portion of the frame can be formed by carrying up the sides ofth'e casingcasting, and the construction issimplifie'dt While the apparatus given in thedraw- .ings shown,-is adapted to be actuated b hand, it may be operated by" power we as an electric motor or motors connected with the operating parts, and, say, supported on or attached to the casing.

What is claimed is A ships davit comprising a casing in which the davit is mounted for movement, mechanism for operating the davit housed within the casing, the casing being formed to provide a neck through which the davit extends and in which it swings, a cover for the neck carried bythe davit and operating in allpositions of the davit to seal the opening in the neck, said casing being formed with an opening through which a portion of the davit extends in operation, and a housing resting upon the casing to close said opening and receive said extended JOHN SCOTT VALENTINE HARRISON. 

